Age-Inappropriate Dress: Even when their face is wrinkled and their hair is gray, the main character's outfit never changes. An old man or woman running around in the clothes they wore as a teenager is...quite an interesting spectacle.
Heroic Mime: S/he never says a word - every interaction with another character is done with changing facial expressions, nods or shakes of the head, and occasional charade-like actions. The choices you choose count as dialogue though.
Cool Old Guy: Takakura in AWL may be silent and more than a little distant with you, but he has the farm's best interest always in mind, and is a sort of father figure to your character after your own dad died in the beginning of the game.
Lost Forever: If you're not good enough friends with her, she'll leave the valley permanently. If you ARE, she'll claim she's leaving the valley forever... but she decides to stay. She likes Forget-Me-Not Valley too much.
Maternally Challenged: Fights with her son, goes off to the bar every night, and spends most of her days wandering aimlessly outside. The baby will be fine on his own...
Lonely Rich Kid: Unless you do anything about it, the only person she will ever have to talk to is her elderly butler, her high maintenance grandma, or ROCK.
No Accounting for Taste: In DS, she eventually marries the playboy Rock. Most of their events afterwards involve them getting into fights with one another. (Heck, even their rival events are Slap-Slap-Kiss!)
Older Than They Look: She's fifteen in the original Japanese Wonderful Life series. She looks like a preteen, though.
Rags to Riches: Inverted, if you marry her she happily goes from richest girl in town living in an enormous mansion on top of a hill to farmer's wife down by the river.
However it should be noted that the player character can earn a LOT of money as a farmer. So that inversion can be subverted depending.
Break the Cutie: In AWL if you bring her up to three hearts and see all of her events, then choose to marry someone else, it means she left her arranged marriage for nothing and shatters her heart, she, Vesta, and especially Marlin will never forgive you.
Education Mama: In AWL she really wants to see her son grow up to be a scientist, and always wants him to be studying.
A waitress who works at the Blue Bar. Perennially loveless, she often laments her ill luck with men. (Worse still, she doesn't seem to realize the affection that bar owner Griffin has for her.) She's a rather feminine girl, taking delight in makeup and jewelry.
All There in the Manual: If not for her age being cited as thirty in the manual, you really wouldn't be able to tell.
Looking for Love in All the Wrong Places: In ANWL Muffy can be seen crying now and then by the river over the latest boyfriend in the city who's broken her heart. Whether he was cheating on her, or secretly using her as his mistress, she always simply convinces herself that she'll find her man one day. But... since you can't marry her in the game, she never does.
May-December Romance: Her designated love interest (outside of the player) is Griffin, 16 years her senior. She only marries him in Harvest Moon DS/Cute, though.
She's also about seven to nine years older than the player character.
Getting Crap Past the Radar: "When it's this hot, lots of girls like to go to the beach in sexy swimsuits.Suddenly I feel like surfing."
Happily Adopted: Well...sort of. If you marry Rock, his dad will comment that Rock was "like a son to them". Rock becomes flustered and changes the subject. Add this to several other hints in the game, as well as the fact that Rock looks nothing like them and...yeah.
This and That: In the first heart event, he asks if you want to go with him to the swamp for "this and that".
A ranch hand, and Vesta's brother. He moved out to the valley when he was young because of his failing health, and he's still a bit frail. He can be cold at first, but when he warms up, he shows himself to be a kind-hearted person. He does tend to worry, though.
Ill Boy: He was one in his childhood; he's still somewhat fragile.
Jerk with a Heart of Gold: Varies depending on the game and actions. In AWL he will not be nice to you if you pursue Celia, but if you marry someone else he'll be a good drinking buddy. And in ANWL he becomes more like a very shy guy who just happens to not smile often.
Yandere: There is an optional scene in which he muses over Celia's beauty, which ends with him saying "I'll decide who's good for Celia and who's not!"
A songwriter who lives in the valley, and something of a hippie. He's a loner and a wanderer, but he'll befriend you if you like—he might even show you some of his music. He's pretty in-tune with nature. He likes Nami; he's attracted to fellow loners.
Ascended Extra: He went from being a rather pointless character in AWL to one of the three potential spouses in ANWL.
Erudite Stoner: He's not stoned as far as we know, but he acts like it sometimes...
Younger Than They Look: He's really the second-youngest bachelor after Rock, but people tend to treat him as if he's much older. Must be the beard. To drive this even further, Gustafa is the only bachelor who will never age, and by the end of the last chapter will still look the same as the day you met him, compared to rock and Marlin whose hair starts to grey by the second chapter.
The owner of the local bar. Griffin is an aging gentle guy who has a small crush on Muffy. In Harvest Moon DS Cute he is a marriageable bachelor.
Grant's wife and Kate's mother who move into town in the second chapter.
Bitch in Sheep's Clothing: She seems to be an incredibly high maintenance woman, impatient with guests and her daughter, and Grant tries his hardest to avoid coming home from work for as long as possible because of her.
The Ghost: She is noticeably missing in Harvest Moon DS. It's explained that Grant finally got the good sense to divorce her.